In the injection molding process melted thermoplastic and thermosetting polymers are heated and forced into a mold during an injection process. The mold can be in the form of a die made of two halves. A witness line, also known as a parting line, extends in the formed piece where the two mold halves abut one another.
For many applications the witness line poses no problem and the formed product functions perfectly fine. However, in other applications a significant problem arises because of the parting line. For example, in applications where tight clearances are required and the molded part requires smooth surfaces the parting line quickly becomes a problem. For example, where O-rings abut parting lines leakage may occur.
Thus, there is a need for an apparatus and method for eliminating or smoothing out the parting line in products formed by injection molding and other molding methods.